I watched a show the other day on the new mitsu EVO, and the dude was saying how fast it is, which it is, i love that car. BUT, he did 30MPH and he said he had it in high gear, and some other POS car was faster then him, on a roll. He said the turbo lag was so bad.

I always liked the dodge neon SRT, and that little car has a big 4 cyl, with turbo, and i always wondered..how the hell does lag feel..?

I watched a show the other day on the new mitsu EVO, and the dude was saying how fast it is, which it is, i love that car. BUT, he did 30MPH and he said he had it in high gear, and some other POS car was faster then him, on a roll. He said the turbo lag was so bad.

I always liked the dodge neon SRT, and that little car has a big 4 cyl, with turbo, and i always wondered..how the hell does lag feel..?


LOL yes the infamous Clarkson, don't always take him seriously. He likes to exagerate stuff often and to make stupid jokes. His show is awesome though.

Basically what he did was, exagerate the effects of turbo lag, who in their right mind would use 6th gear to accelerate from 30mph.

Anyway most of the time turbo lag is far overexagerated, yes it exists but in most cars especially modern ones with a properly matched turbo turbines and compressors it will not be a big issue.

Also if you really think about it basically all NA cars have a "turbo lag" that never ends. Because turbo lag is is basically the NA power of the turbo engine. However this "lag" is felt more in turbo cars because they have ussually lower NA power due to a slight exaust backpresure and lower CR plus when the boost kicks in the power difference is so large that the previeous power levels seems ridiculous. In an NA car you'll never feel this difference because there is no boost to kick in so you basically don't know what you are missing;)

Now there is also a big difference between turbo cars as far as exibiting lag. The smaller the engine and its CR and the bigger the turbo the more lag you'll feel and viceversa. But even in the EVO for example which has only 2.0L and a pretty big turbo the lag is not that bad and the new 05 models are even better due to turbine redesign. Only if you want to push that evo to 400,500,600 hp or other huge amount requirering a huge turbo you'll have big lag issues. And even then lag will be an issue only if you are caught flat footed, but if you are ready to race you'll have that engine under load threfore spinning that turbo. Also in case of road racing only super tight corners can drop you into lag territory but there are ways to minimise that problem.

And to answer your specific question about SRT4. Lag in that car is virtually non existent. I have quite a bit of dirrent experience with this particular car and let me put it this way: it pulls like a muscle car from low rpm. Actually its full 250TQ starts as low as 2400RPM. And even with the stage 3 large turbo upgrade it still has a sick powerband.

And as they say a picture is worth a 1000 words here is the dyno sheet of a stage 3 SRT4:


http://www.mopar.com/img/dyno_srt4_s3.gif

just look at that TQ curve. Does this seems like a car where lag is a problem in power delivery?;)


PS. I hope I was clear enough, its 4 am here and i really should be slepping and nost posting while my cognitive functions are significantly impared.

Wow thanks. Yeah i love both the evo and the srt4, everyone bashes both these cars, saying like if they didn't have turbo, they'd be grandma cars..True, BUT, if muscle cars has 200hp, they'd be slow as dog shit.

I personally NEED a car with torque, especially if you hang with alot of people and all that weight get in the car. My 270ftlbs torque tbird does a decent job..

Forgot to mention, yeah, why the hell would anyone accelerate in 6th gear, at 30MPH. Lol, i can get in a 801hp Z06, in gran turismo 3 aspec, and put it in 6th, on a roll of 30mph, and it's slow as shit..

Lol, best game ever..

I have a 96 Impala that used to be my wife's daily driver. There was a time that an 87 Grand National was my daily driver. My wife would occasionally drive the GN and hated it. She was used to the instant power of the Impala and would go to pull out into traffic. She would say "It wouldn't go and I gave it more gas and it wouldn't go so I gave it more gas and then all of a sudden it was sideways". The GN was running big turbo and 20psi of boost so it had lots of lag and when the turbo came in it more than doubled the power. In a rolling race the Impala would put a half car length on the GN and then the GN would pull away like the Impala was standing still. The more boost the more lag.

Lag is overrated. I get spool at 3500-4000rpm and I love it.

3500-4000 RPM??? Man you got slow spool. With the stock turbo I got full boost of 15 PSI by 2800 RPM. Now with this S70 I get full boost around 3200. And thats with a turbo thats capable of 350 WHP on a 8 valve head.

I feel bad for these Honda guys that buy full hybrid T3/T4 turbo's for their 1.8L with .82 A/R turbine housings to accomplish 250 WHP and not have full boost until 6000 RPM. I have a straight T3 turbo and getting 300 HP with an 8V head. Oh and did I mention 350 ft/lbs of torque? LOL

lag in a super powerful car with late boost is great. if you misshift or jsut wnat ot have fun and your boost drops and you get on it agian you are just slightly pulling and yo ucould still lean up if yo uwanted to but hten boost hits and you cant move your mouth and you are strugleing to keep your head up. thats a feeling. sort of like going up a steep incline on a rollercoaster after going down a huge high speed drop. but if a properly sized turbi is used full boost should hit by the mid 3,000's for sure. some even as low as 2,000RPM.

Well, if you get full boost by 2000 RPM your turbo is too small. Full boost by around 3000 RPM is good, for a bigger turbo around 3500 is good. But if you are using a stock turbo (on a factory turbo car) you should have full boost by 2500 RPM. But sometimes the ECU will limit boost until a certain RPM, in that case it does not count. I'm talking about if you are running a manual boost controller.

A turbine housing is a compromise between full boost engine speed and top end restriction. As stated above a turbo that reaches full boost by less than 3000rpm is leaning a little in the restrictive direction and 2000rpm is way too far. Big turbos are best suited with automatics with higher stall speed convertors where the engine does not operate below 3000rpm anyway. A big turbo with a manual or factory torque convertor is a less than ideal setup.

I agree with your first part, but about the second part I disagree. Big turbo's are fine on manual tranny's, you can keep the RPM's up whereas unless you are running a manual valve body you are gonna shift and lower the RPM's. Auto tranny's need a smaller turbo so you can brake-torque it and come off the line like a bullet. This is better for drag racing not for the street, because with street tire's you'll never get traction. Also, a manual trans tipically has more gears, so the RPM band stays higher and you also accelerate faster. It's just off the line that suffers, but again thats not necessary for a street car.
Of course, this all hinges on what you and I consider ''big''. I consider anything full hybrid T3/T4 to be big. Right now I'm running a moderate turbo, it's a straight T3 though. A GN wheel (AKA super 70) with a .63 A/R turbine stage 1 wheel. On a 16 valve engine such as a honda the turbo is capable of 400 WHP. This is why it angers me to see turbo kits out there for honda's that come with bigger turbo's than I am running. It's absolutely stupid to run a 50-57 trim hybrid at 6-8 PSI on a honda and not have any boost until 5000 RPM. That turbo is meant to be run at 25-35 PSI levels.

You made an important point. It all depends on what you think "big" is. My car makes 456Hp and 609lb-ft at the rear wheels. T64E @ 12psi .85AR You don't get manuals that will hold up to that. I was focusing on strait line performance. I have rear wheel drive and good tires (I consider Nittos street tires) so I can put it all down even on the street. Most high powered or what I consider high power use a transbrake to build boost at the line as you describe. For a strait line all else being equal an auto with high stall and transbrake will always beat a manual even on the street.

Maybe for a GN you cannot find a manual tranny to hold up to those powel levels, which I still find that hard to believe because I know a guy that dyno'd 373 WHP and 425 ft/lbs in a daytona with the 2nd strongest tranny not even the beefiest one. And I'm sure that tranny will hold more too. If Chrysler can make a bone stock FWD tranny to hold up to those power levels, well....
I have the 3rd strongest tranny in my daytona and I'm pushing 300 WHP, but thats maxxing it out.
I prefer a manual on the street because it's more fun. A manual valve body auto is cool too, but you still don't have as many gears. Also, auto tranny's will have more drivetrain loss.
From a dead stop, everything being equal the auto would probably win on the street simply because of the launch. But from a roll, different story.

Garrett T04B .69ar turbine P-Trim turbine wheel on a 2.4 DOHC. I had the late boost in mind so the car drove like it was NA in everyday driving. It is sized properly. I don't drop out of boost when shifting.

so would a bigger turbo be worth the longer lag on a small engine?
or should smaller engines just stay away from big turbos?

i have turbo lag so bad, it sucked the pistons right out of their cylidners.

You can make all the torque you want in a front drive car and not worry about a good manual tranny. Even with slicks the tires will slip long before there is enough load to break anything. Put a manual in between a good clutch and a sticky tired rear drive car and put a few hard launches on it and it will not even hold up to its advertized rating.

What??? Thats your reason? LOL, how about...no. Except for 1st gear I can get traction on street tires with my 350 ft/lb engine in my daytona. Why? A well balanced front end (not even an LSD!) and very stiff rear suspension to stop rear end squat on acceleration. That 373WHP/425 ft/lb Daytona I mentioned runs 11.3 ET's, can't do that without traction.

http://community-2.webtv.net/MR-2-2-TURBO/22TURBOPOWERHOMEPAGE/

Just because you drive fast RWD cars does not make FWD cars crappy and not able to get traction.
Here's a 9 second FWD car if you are still not satisfied-
http://www.thedodgegarage.com/9_sec_club.html
I'd think you would have to get good traction to runs mid 9's eh?

so would a bigger turbo be worth the longer lag on a small engine?
or should smaller engines just stay away from big turbos?

It depends on your preferences, and also what you consider to be a big turbo. My personal preference, on a sub 2 liter 4 cylinder engine there's no need to go to a full hybrid on a street daily driven car. A straight T3 turbo can accomplish 400 WHP and have full boost around 3500 RPM. T3/T4's should only be used on race engine 4 cylinders because there is no need for them on street 4 cylinder cars. Again this is my personal preferences.
Look at my sig, I have 300 WHP on an 8 valve head with a straight T3 no hybrid. Typically a 16 valve head yields 30% more HP than an 8V head, so I would have almost 400 WHP with a 16V head swap. IS that not enough for a 4 cylinder daily driver on pump gas? LOL

the turbo has the potential to make 300HP but would a small (1.6L vtec honda) engine be able to put enough power to the turbo to get near 200 HP. or any other engine

I originally said manual trannys won't hold up to 600+ lb-ft. My definition of holding up is never having to worry about it breaking. I'm sure people have been faster than 8's with mannuals but that proves nothing. They are living on borrowed time. You can say alot of good things about a manual when comparing them to an auto but strength is not one of them.

Apparently then you are not familiar with Tremec 5 and 6 speeds? People push 1000+ ft/lbs through them with big block Chevy's with ease. They make retro-fit kits for muscle cars to put in new technology tranny's in with overdrives but can still take the abuse of big block power backed by a lifetime warranty.

Stock for stock I know of no auto tranny thats stronger than an manual. The auto has to be ''built up'' to handle to power. The stock clutch on a manual might wimp out though, but the tranny itself is stout. Case in point look at dodge rams with the Cummins diesel...my bro is putting 850 ft/lbs through his 6 speed and the stock clutch just started slipping but try that with an auto KABOOM!

so would a bigger turbo be worth the longer lag on a small engine?
or should smaller engines just stay away from big turbos?


it depends on you aplication. for street driving an overly large turbo can be anoying. In racing it depends on the track. A slow road course with numerous hairpins will be terible for a laggy setup same goes for autox while a high speed course or an oval would fit perfectly a large turbo since there will be no oportunities to get off boost.

I originally said manual trannys won't hold up to 600+ lb-ft. My definition of holding up is never having to worry about it breaking. I'm sure people have been faster than 8's with mannuals but that proves nothing. They are living on borrowed time. You can say alot of good things about a manual when comparing them to an auto but strength is not one of them.


I most certainly do not agree. There are numerous vipers and supras running far more than that on trheir manual trannnies and those are just two examples.

And lets not forget that most top level forms of motor sports run manual trannies. That includes F1, Lemans, WRC etc. And if your going to say no those are sequential lets me remind you that sequential trasnmisions are nothing more that manuals that shift for you.

Also I'm not the biggest expert in drag racing but don't they use in pro drag racing a fairly similar setup to manual transmissions? I know that they do use clutches because here is a site that sells them:http://www.ramclutches.com/

Tremec's best tranny is the 3550 which is rated at 550lb-ft. My friend has one in his mustang that he is trying to get in the 9's with. He only makes about 10 passes per rebuild but wants to do it with a manual. If he lines up we all watch because there is a high chance there will be a good pop and the front end of his car drop back down before he reaches the 60'. It is silly to make the statement that they offer a tranny with a lifetime warrenty. No one offers a tranny with a lifetime warrenty for a high performance application.

If you want to bring up formula cars you may have a point. They are strong but I certainly don't know how to get one or put it in my car so that too is silly. 18 wheelers have manuals too but it would kind of dumb to bring that up in a discussion about street cars. You bring up Vipers. The Hennesy (sp) twin turbo Viper runs nines. It is converted to an auto. Lingefelters twin turbo vette.. auto.

Some high powered drag cars use the manuals with the sticks that you pull back. Most people don't know but these are made up of planetary gears. They are built like an auto with no torque convertor.

Nissan KA24DE manual trannies hold 530+whp and came from the factory with 155BHP.

Since when can auto trannies hold more than manuals stock for stock? Whatever you spend to upgrade the auto, spend the equal amount upgrading the manual and see who wins. Manual transmissions are stronger by design than autos.

Auto trannys use planetary gearing which is in constant contact and has contact at multiple points. Automatics are inherently stonger.

LOL, looks like you are getting outvoted here Andy. Tell me a factory car that has a stronger Auto tranny than manual?

KA24DE/-T engines are truck engines, no wonder their transmission can hold so much power and torque. They were build to get the crap beat out of them. Auto trannys have the potential to blow because they have ball bearings and other tiny trinkets in them that can blow holes in the tranny. plus, fluid can only handle so much pressure in a confined space. Thats why you hear of auto trannys cracking. The fluid has to go somewhere. Gears are stronger and do not blow the shit out of a housing like an auto can. But teeth can be ripped off and weaken the housing causing it to fail. Anyways like i said before, the pistons in my car got sucked out of the cylinders.

87-92 Z28, Firebird Formula, etc. with 350 could only be purchased with an auto. If you got the 305 you had the option between the manual (T5 which is the same manual that gt mustangs had in those days) and auto (called 700R-4 until about 90 then called 4L60 but they were the same tranny). GM didn't have a manual tranny with overdrive that would handle the 325lb-ft of the TPI 350 until 93 when they got the T56.
The T56 is the strongest manual I know of that is widley available. The Viper version with the better gearing is rated at 550lb-ft. Lots of guys get them to last a long time behind a 600+lb-ft engine but many of the guys that go to the track a put some abuse on them are breaking them.

I am not making the statement that stock to stock autos are stronger. The example I gave was but I know that most cases are the opposite. The problem is manual trannys are not upgradeable like autos are. I don't know of any stock trannys manual or auto that will take the kind of abuse I am talking about but you can readily buy beefed up autos that will.

Another inherent advantage of the auto from a strength standpoint is the torque convertor. It cushions the tranny from the engine. One of the big no nos in the auto world is to lock the torque convertor at WOT. Lots of aftermarket chips and programers do this to auto cars because it increases the effeciency and makes the car a little faster but it will reduce the life of the tranny.

Ever heard of a toploader? You can build those bastards to take 750+hp/tq without batting an eye. My friend builds them all the time... When I switch to manual(twin turbocharged 351c/5.8L) I'm going to have him build me one... He'll do it for around $700 for a tranny that'll take 750hp. It cost me $850 to have my C4 built to take 550hp.

87-92 Z28, Firebird Formula, etc. with 350 could only be purchased with an auto. If you got the 305 you had the option between the manual (T5 which is the same manual that gt mustangs had in those days) and auto (called 700R-4 until about 90 then called 4L60 but they were the same tranny). GM didn't have a manual tranny with overdrive that would handle the 325lb-ft of the TPI 350 until 93 when they got the T56.


You gave the wrong example with me...
I have 3 friends with camaro's. One has a 92 Z28 auto 350 TPI all stock except exhaust that has gone through (3) 700R4 tranny's in the past 2 years.
Another friend with a 90' 305 TBI 5 speed but has been built to 325 WHP, no problems whatsoever tranny wise but it has a new centerforce clutch.
Another friend with an 88' TBI 305 5 speed bone stock, no problems and he drives like a crazy person.

Your experience with three cars would sugest the T5 is as strong or stronger than the 700. I could name some contradictory examples but the bottom line is GM wouldn't allow the t5 to be put behind the 350 and would allow the 700 to. You know a manual sports car is more marketable and people at GM wanted to be able to offer it. I'm assuming whomever made the decision at GM had more knowledge than me or you and experience with more than 3 cars. Despite what you say I will have to go with the GM engineers on this one and say the 700 is stronger than the t5.

The 700 R4 has been known for being weak, not just this one instance. And if the OEM was so great, why is there such a big aftermarket for these cars or even any car?

Strength might not have been the reason a manual wasn't offered, there may be other reasons too. Can you provide proof that it was strength issues as the reason GM didn't use the T5 with the 350?

As much as I like to debate you have worn me down. I'm out.

I avoid 700R4's like the plague, I've heard way too much bad about them. It's a TH400 for me, who cares about overdrive when strength is a concern.

i couldent read all the posts but the best way i can see to beat turbo lag and still have a shitload of boost and a realy big turbo... is to have a chain of turbos... 2-4 turbos a small one and a large one... i cant remember but there was a setup that once u hit the full power of the small turbo and were at enough RPMs to power up the large one the 2nd one started and the 1st one stoped... letting more boost come in and creating more power... TAKES ALOT OF CASH but hey not to much turbo lag...

i couldent read all the posts but the best way i can see to beat turbo lag and still have a shitload of boost and a realy big turbo... is to have a chain of turbos... 2-4 turbos a small one and a large one... i cant remember but there was a setup that once u hit the full power of the small turbo and were at enough RPMs to power up the large one the 2nd one started and the 1st one stoped... letting more boost come in and creating more power... TAKES ALOT OF CASH but hey not to much turbo lag...

This is common for diesel engines, not so much for gas engines it's doesn't work the same.

To avoid lag of a large turbo, there are 2 well known ways. Nitrous, or compressed air shooting in the turbine.